rdns dev here
Both the server and the Android client are fully open source, too. We’re currently working on a low-cost DNS resolver (500million/reqs for $1 as opposed to $100 that it costs us today), as traffic has substantially ramped up in the recent months (around ~5k reqs/sec, right now).
(in fact, the deployments are “open” as well: ⛅ CF · Workflow runs · serverless-dns/serverless-dns · GitHub)